Simpson's evenness index (Diversity metric)
lsm_l_siei(landscape, directions = 8)tibble
Raster* Layer, Stack, Brick, SpatRaster (terra), stars, or a list of rasterLayers.
The number of directions in which patches should be connected: 4 (rook's case) or 8 (queen's case).
$$SIEI = \frac{1 - \sum \limits_{i = 1}^{m} P_{i}^{2}} {1 - \frac{1} {m}}$$ where \(P_{i}\) is the proportion of class i and \(m\) is the number of classes.
SIEI is a 'Diversity metric'. The metric is widely used in biodiversity and ecology. It is the ratio between the actual Simpson's diversity index and the theoretical maximum Simpson's diversity index.
None
0 < SIEI <= 1
Equals SIEI = 0 when only one patch is present and approaches SIEI = 1 when the number of class types increases while the proportions are equally distributed
McGarigal, K., SA Cushman, and E Ene. 2012. FRAGSTATS v4: Spatial Pattern Analysis Program for Categorical and Continuous Maps. Computer software program produced by the authors at the University of Massachusetts, Amherst. Available at the following web site: https://www.umass.edu/landeco/
Simpson, E. H. 1949. Measurement of diversity. Nature 163:688
lsm_c_pland,
lsm_l_pr